Structural Audit of Buildings in India — Complete Guide for Owners, Engineers, and Developers (2026)

India's building stock is ageing rapidly. According to Census 2011 data, over 11 million residential buildings across the country were constructed before 1980 — meaning they are now 45+ years old. Many of these structures were designed before India adopted its modern seismic code (IS 1893:2002), before concrete durability provisions were tightened in IS 456:2000, and before municipal corporations had the administrative machinery to enforce construction quality.

The consequences are visible every monsoon season. Building collapses in Mumbai, Lucknow, Delhi, and smaller cities kill hundreds of people every year. In most cases, the root cause is the same: aged concrete, corroded reinforcement, foundation settlement, or unauthorised structural modifications — all problems that a timely structural audit would have flagged.

This guide explains what a structural audit is, which Indian states mandate it and at what building age, which IS codes and testing methods are involved, what the audit report contains, how much it costs, and what repair or retrofitting options exist when the results are unfavourable.

What is a structural audit?

A structural audit is a systematic examination of a building's structural system — foundations, columns, beams, slabs, walls, and connections — by a qualified structural engineer to determine whether the building is safe for continued occupancy.

It is not a visual walkthrough. A proper structural audit combines:

• Visual inspection — crack mapping, spalling, exposed reinforcement, dampness patterns, settlement signs, and material deterioration
• Non-destructive testing (NDT) — in-situ tests on concrete and steel without damaging the structure
• Destructive/semi-destructive testing — core extraction, chemical analysis when NDT results are inconclusive
• Document review — original structural drawings, soil investigation reports, past repair records, and occupancy change history
• Structural analysis — re-checking load paths and member capacities against current code requirements (IS 456, IS 1893, IS 875)

The output is a structural audit report that classifies the building into a safety category and recommends specific repairs, strengthening measures, or — in extreme cases — demolition.

Structural audit vs visual inspection vs condition assessment

These three terms are often used interchangeably, but they serve different purposes:

A structural audit is the most comprehensive of the three. Municipal corporations accept only structural audit reports from registered engineers for regulatory compliance.

Why structural audits matter in India

Ageing building stock

India's urban building stock is among the oldest and least audited in the world:

• Mumbai: MHADA (Maharashtra Housing and Area Development Authority) has identified over 14,000 buildings as "cessed" (old and dilapidated) in the island city alone. As of 2025, the BMC's dangerous building list includes thousands of structures classified as C1 (demolish immediately) or C2 (major repairs needed).
• Delhi: An estimated 40% of residential buildings in old Delhi areas are over 50 years old with no structural audit on record.
• Kolkata: KMC has identified over 3,000 buildings in the "dangerous" category, with many in Bowbazar, Burrabazar, and north Kolkata dating to the early 1900s.
• Chennai: Corporation of Chennai has flagged hundreds of buildings for structural vulnerability, particularly in George Town and Mylapore.

Building collapses — the human cost

Building collapses in India are not rare events. They are a recurring pattern driven by ageing infrastructure, illegal modifications, and the absence of mandatory structural audits in most cities:

• Navi Mumbai (2024-25): The Navi Mumbai Municipal Corporation identified 513 buildings as dangerous structures in its 2024-25 survey and set a deadline of 31 March 2026 for structural audit completion and report submission.
• Vadodara bridge collapse (July 2025): A 40-year-old bridge collapsed in Vadodara, Gujarat, killing 18 people. Investigations revealed that no structural audit had been conducted since construction.
• Mumbai monsoon collapses: Every monsoon season, Mumbai records multiple building collapses in areas like Dongri, Bhiwandi, Malad, and Kurla. Most victims are residents of old chawls and tenements that were never structurally audited.

The National Crime Records Bureau (NCRB) data shows that building and structure collapses account for hundreds of accidental deaths annually across India. The actual number is likely higher because many incidents in rural areas and smaller towns go unreported.

Regulatory gap

Unlike fire safety (which is regulated nationally through the National Building Code / NBCS 2026) or environmental clearance (which is regulated by MoEFCC), structural audits have no uniform national mandate in India. The requirement varies by state, city, and sometimes by ward within a city. This patchwork creates dangerous gaps where buildings in one municipality are audited regularly while identical buildings across the boundary line have never been inspected.

State-wise mandatory structural audit rules

Maharashtra — the most comprehensive regime

Maharashtra has the most developed structural audit framework in India, driven largely by Mumbai's long history of building collapses.

Legal basis: Section 353B (sometimes cited as Section 355B) of the Mumbai Municipal Corporation Act, 1888.

Key rules:

Building classification system:

Who can conduct the audit: Only structural engineers registered with the Municipal Corporation (BMC, TMC, PCMC, etc.) are eligible to conduct structural audits and issue stability certificates.

Submission: Owners must submit the structural stability certificate to the assistant commissioner of their ward within 30 days of publication of the notice by the municipal corporation.

Penalties for non-compliance: The municipal corporation can disconnect water and electricity supply, impose fines, or initiate eviction proceedings if the owner fails to submit the audit report within the prescribed timeline.

Enforcement bodies: BMC (Brihanmumbai Municipal Corporation), MHADA, CIDCO (for Navi Mumbai), and municipal corporations of Pune, Nagpur, Thane, and other cities.

Gujarat — GDCR 2017 framework

Gujarat's Comprehensive General Development Control Regulations (GDCR) 2017 include specific structural audit provisions.

Building classification for audit purposes:

Key requirement: A Structural Engineer of Record must inspect the building and certify structural stability through a Structural Inspection Report. The owner must submit the certificate to the Competent Authority no later than one month after the inspection is due.

Enforcement: Gujarat's urban local bodies (Ahmedabad Municipal Corporation, Surat Municipal Corporation, Vadodara Municipal Corporation) are responsible for enforcement. Non-compliance can result in building use restrictions and notices under the Gujarat Municipalities Act.

Delhi — MCD and DDA requirements

Delhi's structural audit requirements operate under multiple agencies:

• Municipal Corporation of Delhi (MCD): Buildings older than 30 years require structural audit. MCD's Unified Building Bye-Laws 2016 emphasise structural safety compliance.
• Delhi Development Authority (DDA): For buildings on DDA land, structural safety certificates are required during mutation and transfer of property.
• New Delhi Municipal Council (NDMC): Lutyens' Delhi area has separate provisions for heritage and old structures.

Current status: Enforcement is less strict than Maharashtra. While the rules exist, the absence of a systematic notice-based audit programme means compliance is largely voluntary for most residential buildings.

Tamil Nadu — TNCDBR provisions

Tamil Nadu Combined Development and Building Rules (TNCDBR) 2019 mandate structural safety compliance. Chennai Corporation has conducted drives to identify structurally vulnerable buildings, particularly in heritage zones (George Town, Mylapore, T. Nagar).

However, Tamil Nadu does not have a systematic age-based mandatory audit framework comparable to Maharashtra or Gujarat. Structural audits are typically triggered by:

• Complaints from residents or neighbours
• Visible structural distress observed during municipal inspections
• Applications for building plan approval for additions or modifications

Kerala — post-flood requirements

After the devastating floods of 2018 and 2019, Kerala has increased attention to structural safety:

• Buildings in flood-affected areas were assessed for structural damage
• The Kerala Municipality Building Rules require structural stability certificates for buildings undergoing major renovations
• Local Self Government Department has issued guidelines for structural assessment of flood-damaged buildings

West Bengal — KMC provisions

Kolkata Municipal Corporation (KMC) has identified over 3,000 buildings in the "dangerous" category. KMC's Building Rules include provisions for:

• Structural audit of buildings older than 30 years
• Mandatory assessment after fire, earthquake, or flood damage
• Audit before approval of additional floors or change of use

Other states

IS codes relevant to structural audits

The following Indian Standards (IS codes) form the technical foundation for structural audit methodology:

Structural design and evaluation codes

NDT and testing codes

Repair and strengthening codes

Non-destructive testing (NDT) methods

NDT tests assess concrete quality and reinforcement condition without damaging the structure. These are the primary diagnostic tools in any structural audit.

Rebound hammer test (IS 13311 Part 2)

What it measures: Surface hardness of concrete, which correlates approximately with compressive strength.

Procedure:

1. Remove plaster/finish to expose bare concrete surface
2. Smooth the surface using carborundum stone
3. Hold the Schmidt hammer perpendicular to the concrete surface
4. Record rebound values at 12-15 points on each member
5. Discard readings that differ by more than 6 units from the average
6. Use the manufacturer's correlation chart to estimate compressive strength

Interpretation:

Limitations: Surface moisture, carbonation, aggregate type, and surface finish affect readings. Rebound hammer gives an indication, not a definitive strength value. Always confirm with core tests when rebound values are low.

Cost: Rs 300-600 per test point (2026 rates, varies by city).

Ultrasonic pulse velocity (UPV) test (IS 13311 Part 1)

What it measures: The speed of ultrasonic waves through concrete, which indicates density, homogeneity, and presence of internal defects.

Procedure:

1. Apply coupling agent (grease or petroleum jelly) to transducer faces
2. Place transmitter and receiver on opposite faces (direct method), same face (surface method), or adjacent faces (semi-direct method)
3. Record pulse transit time
4. Calculate velocity = path length / transit time

Interpretation (as per IS 13311 Part 1):

Advantages: Detects internal voids, honeycombing, cracks, and delamination that are invisible from the surface. Can be used to assess fire-damaged concrete.

Cost: Rs 500-1,000 per test location.

Half-cell potential test (ASTM C876)

What it measures: The probability of active corrosion in reinforcing steel embedded in concrete.

Procedure: A copper-copper sulphate reference electrode is placed on the concrete surface, and the potential difference between the electrode and the reinforcement is measured using a high-impedance voltmeter.

Interpretation (ASTM C876):

When to use: When concrete shows rust stains, spalling, or when carbonation depth exceeds the concrete cover.

Carbonation depth test

What it measures: How deep carbon dioxide from the atmosphere has penetrated into the concrete, reducing its alkalinity and removing the protective passivation layer around reinforcement.

Procedure:

1. Drill or break a fresh concrete surface
2. Spray phenolphthalein indicator solution (1% in ethanol) on the freshly exposed surface
3. Concrete that turns pink/magenta is alkaline (pH > 9) — not carbonated
4. Concrete that remains colourless is carbonated (pH < 9)
5. Measure the depth of the colourless zone from the surface

Significance: When carbonation depth reaches the reinforcement, corrosion begins even without chloride exposure. In coastal cities and industrial areas, carbonation progresses faster.

Cover meter / rebar locator scan

What it measures: The depth of concrete cover over reinforcement and the location, spacing, and diameter of rebars.

Equipment: Profometer, Ferroscan, or similar electromagnetic devices.

Why it matters: IS 456:2000 specifies minimum cover requirements based on exposure condition:

Buildings with inadequate cover are more susceptible to corrosion. Cover meter scans reveal whether the original construction met code requirements.

Destructive and semi-destructive tests

Core testing (IS 516)

When NDT results are inconclusive or when accurate compressive strength is needed, concrete cores are extracted from structural members.

Procedure:

1. Identify test locations (avoid reinforcement using cover meter)
2. Extract cylindrical cores using a diamond-tipped core drill (typically 75 mm or 100 mm diameter)
3. Record core dimensions and examine for voids, honeycombing, and cracks
4. Cap the core ends and test in compression per IS 516
5. Apply correction factors for length-to-diameter ratio

Acceptance criteria (IS 456 Clause 17.4): Concrete is considered acceptable if the average equivalent cube strength of the cores is at least 85% of the specified grade, and no individual core has strength less than 75%.

Caution: Core extraction damages the structure (holes must be grouted after testing). Limit cores to the minimum number needed to establish strength reliably. Typically 3-6 cores per building floor.

Chemical analysis

Laboratory tests on concrete powder or core samples can determine:

• Cement content — whether the original mix had adequate cement
• Chloride content — risk of chloride-induced corrosion (common in coastal buildings)
• Sulphate content — risk of sulphate attack (common in areas with high water table)
• Alkali content — risk of alkali-silica reaction (ASR)

Load testing (IS 456 Clause 18)

For critical structures where analytical evaluation is insufficient, in-situ load testing may be conducted:

• Apply test load = design dead load + 1.25 times design imposed load
• Measure deflection under load and recovery after load removal
• Acceptance: recovery must be at least 75% of maximum deflection within 24 hours of load removal

Load testing is expensive and disruptive. It is typically reserved for bridges, industrial floors, and public assembly structures.

Step-by-step structural audit process

Step 1: Appointment and document collection

• Building owner or housing society appoints a structural engineer registered with the municipal corporation
• Engineer collects: original structural drawings, soil report, approved building plans, occupation certificate, past repair records, and insurance documents
• If original drawings are unavailable (common for older buildings), the engineer prepares as-built drawings through field measurements

Step 2: Visual inspection

• Systematic floor-by-floor, member-by-member inspection
• Document: cracks (location, width, pattern, active/dormant), spalling, exposed reinforcement, dampness, efflorescence, settlement signs, tilting
• Photograph every defect with measurement scale
• Check for unauthorised modifications: removed walls, additional floors, punched openings, heavy equipment on slabs designed for residential loads

Step 3: Non-destructive testing

• Rebound hammer test on representative columns, beams, and slabs (minimum 3 members per floor)
• UPV test on members showing low rebound values or visible distress
• Cover meter scan on all columns and critical beams
• Carbonation depth test on exposed concrete surfaces
• Half-cell potential test where corrosion is suspected

Step 4: Destructive testing (if needed)

• Core extraction from members with consistently low NDT values
• Chemical analysis of concrete samples from areas showing distress
• Reinforcement sampling (coupon test) if rebar corrosion is advanced

Step 5: Structural analysis

• Build or verify the structural model using current code requirements
• Check member capacities against actual loads (including any additional loads from modifications)
• Seismic evaluation per IS 15988 if the building is in Zone III, IV, or V and was designed before IS 1893:2002
• Foundation assessment if settlement or tilting is observed

Step 6: Report preparation and classification

The structural audit report includes:

1. Building description and history
2. Visual inspection findings with photographs
3. NDT and destructive test results with interpretation
4. Structural analysis results
5. Building classification (C1, C2-A, C2-B, or C3 in Maharashtra; equivalent categories in other states)
6. Specific repair recommendations with priority levels (immediate, short-term, long-term)
7. Estimated repair costs with BOQ (bill of quantities)
8. Engineer's stability certificate

Step 7: Submission and follow-up

• Submit the report to the municipal corporation within the prescribed deadline
• If classified C1: building must be vacated immediately; demolition order is issued
• If classified C2: repair work must be completed within the timeline specified by the municipal corporation, and a completion certificate submitted by the structural engineer
• If classified C3: routine maintenance as recommended; next audit as per schedule

Who can conduct a structural audit?

The qualifications required to conduct a structural audit vary by jurisdiction:

Mumbai (BMC)

Only structural engineers registered on the BMC's panel can issue structural audit reports. Registration requires:

• B.E./B.Tech in Civil Engineering from an AICTE-recognised institution
• Minimum 10 years of experience in structural design and construction
• Registration fee and annual renewal

IAStructE accreditation

The Indian Association of Structural Engineers (IAStructE) offers the ASE-IAStructE accreditation:

• B.E. Civil from AICTE-recognised institution
• Minimum 5 years of relevant professional experience in structural engineering
• Examination and interview process

General guidelines for other cities

Where no specific registration system exists:

• Members of the Institution of Engineers (India) — Civil Division
• Members of the Indian Society of Structural Engineers
• Engineers with M.E./M.Tech in Structural Engineering and minimum 5 years of practice
• In some states (Puducherry, Himachal Pradesh), structural engineers must be registered with the Town Planning Authority

Cost of structural audit in India

Structural audit costs vary significantly based on building size, location, number of tests, and the engineer's fee structure:

Typical cost ranges (2026)

Breakdown of costs

Cost of individual tests (2026 market rates)

Note: These are indicative rates. Actual costs vary by city. Mumbai rates are typically 20-30% higher than other cities. Always obtain competitive quotes from at least two registered structural engineers.

Common structural defects found in Indian buildings

Concrete deterioration

• Carbonation: CO2 penetration reduces concrete pH below 9, removing the protective alkaline environment around reinforcement. Progresses faster in buildings exposed to vehicular exhaust, industrial fumes, or high humidity.
• Chloride attack: Common in coastal cities (Mumbai, Chennai, Visakhapatnam, Kochi). Chloride ions penetrate concrete and initiate pitting corrosion of reinforcement even when carbonation has not reached the rebar.
• Alkali-silica reaction (ASR): Reactive silica in aggregates reacts with alkalis in cement, forming an expansive gel that causes internal cracking. Identified through petrographic examination.

Reinforcement corrosion

• Rust staining and spalling: The most visible sign of rebar corrosion. Corroding steel expands to 2-6 times its original volume, cracking and pushing off the concrete cover.
• Section loss: Advanced corrosion reduces rebar cross-section, lowering the member's load-carrying capacity.
• Loss of bond: Corrosion products at the rebar-concrete interface reduce bond strength, affecting structural behaviour.

Structural distress

• Flexural cracks: Vertical cracks at mid-span of beams and slabs, usually at the bottom face. If within IS 456 permissible widths (0.3 mm for severe exposure), they may not indicate a structural problem.
• Shear cracks: Diagonal cracks near beam supports — more critical than flexural cracks and may indicate inadequate shear reinforcement.
• Column cracks: Vertical splitting cracks in columns may indicate overloading or inadequate ties/links.
• Foundation settlement: Differential settlement causes cracks in walls and frames, door/window jamming, and floor slope.

Construction defects

• Honeycombing: Voids in concrete caused by improper compaction. Common in columns and beam-column joints.
• Cold joints: Weak planes where fresh concrete was placed against hardened concrete without proper treatment.
• Inadequate cover: Reinforcement too close to the surface, accelerating corrosion.
• Wrong reinforcement: Smaller bars, fewer bars, or incorrect spacing compared to structural drawings.

Repair and retrofitting options

When a structural audit identifies deficiencies, the repair method depends on the type and severity of damage:

Concrete repair

Structural strengthening

Foundation strengthening

Cost comparison: CFRP vs RC jacketing

A comparative study published in the Indian Journal of Science and Technology found that RC jacketing is more efficient in terms of cost and absolute strength gain, while CFRP wrapping is more efficient in terms of installation speed, lower CO2 emissions, and minimal disruption to occupants. For residential buildings where occupants cannot be relocated during repairs, CFRP is often preferred despite the higher material cost.

RERA implications

Section 14(3) — defect liability period

Under Section 14(3) of the Real Estate (Regulation and Development) Act, 2016, developers are liable to rectify structural defects, poor workmanship, or use of inferior materials for five years from the date of possession.

Key provisions:

• If a structural defect is discovered within 5 years of possession, the developer must rectify it at their own cost
• The developer must complete repairs within 30 days of receiving notice from the allottee
• If the developer fails to rectify within 30 days, the allottee can file a complaint with the state RERA authority for compensation
• The defect liability covers: structural defects, waterproofing failures, plumbing/electrical defects caused by poor workmanship or inferior materials

Landmark RERA orders on structural defects:

Several state RERA authorities have ruled in favour of homebuyers on structural defect complaints:

• MahaRERA has directed developers to conduct structural audits of buildings where multiple homebuyers reported cracks and water seepage within the defect liability period
• Telangana RERA has awarded compensation to buyers for structural defects in newly delivered buildings
• NCDRC (National Consumer Disputes Redressal Commission) has upheld structural defect claims under RERA, even when developers argued that defects were cosmetic rather than structural

Structural audit for RERA compliance

For developers, getting a structural audit at the time of project completion serves as both:

1. Quality assurance — identifies construction defects before handover, allowing the developer to fix them proactively
2. Legal protection — a clean structural audit report at possession date establishes a baseline that can be referenced if homebuyers raise complaints later

Structural audit for redevelopment projects

In Mumbai and other Maharashtra cities, structural audit reports play a critical role in the redevelopment process:

1. Trigger for redevelopment: A C1 classification (demolish immediately) or repeated C2 classifications trigger the redevelopment process
2. Developer selection: Housing societies use the structural audit report as evidence of the building's condition when negotiating with developers
3. FSI benefits: Under the Development Control and Promotion Regulations (DCPR) 2034, buildings classified as C1 or old cessed buildings are eligible for additional FSI (Floor Space Index) as incentive for redevelopment
4. Tenant protection: MHADA and the Rent Control Act provisions protect tenants of buildings classified as dangerous, requiring developers to provide transit accommodation

How Site Setu helps with structural audit documentation

Managing structural audit documentation — from initial notice to final repair completion — involves tracking multiple stakeholders, deadlines, test results, and repair work orders. Site Setu helps construction teams and structural engineering consultants digitize this workflow:

• Document management: Store structural audit reports, NDT test certificates, core test results, and stability certificates in one searchable repository with version control using drawing and document management
• Task tracking: Create WBS-based task lists for repair work recommended in the audit report — assign priority, track progress, and set deadlines
• Quality checklists: Use quality management workflows to create inspection checklists for repair work verification
• Photo documentation: Capture before/after photos of structural defects and repairs with GPS tagging and timestamps
• Progress reporting: Generate daily progress reports for structural repair work with measurement records

Checklist: preparing for a structural audit

Use this checklist to prepare before the structural engineer visits:

• Locate original building plans and structural drawings (check with the architect, municipal records, or society office)
• Gather occupation certificate and completion certificate copies
• Compile records of past repairs, waterproofing work, and modifications
• Document any unauthorised additions or structural changes
• List all complaints from residents about cracks, dampness, tilting, or unusual sounds
• Ensure access to all floors, terraces, basements, and parking areas
• Remove wall coverings or false ceilings in areas showing distress (to allow visual inspection of structural members)
• Clear access to column and beam surfaces for NDT testing
• Keep water and electricity connections active during the audit
• Designate a society representative to accompany the engineer during inspection

FAQs

Is a structural audit mandatory for all buildings in India?

No. There is no uniform national mandate. Structural audits are mandatory in specific cities and states — most comprehensively in Maharashtra (buildings over 30 years, every 5 years) and Gujarat (GDCR 2017 provisions). In most other states, structural audits are triggered by visible distress, complaints, or municipal notices rather than by building age alone.

How much does a structural audit cost in India?

For a typical residential building of 5 floors, the cost ranges from Rs 3-8 per sq ft of built-up area (2026 rates). A 10,000 sq ft building would cost approximately Rs 30,000-80,000 for a complete structural audit including NDT testing, report preparation, and stability certificate. Commercial and industrial buildings cost more due to additional testing requirements.

What happens if a building is classified as C1?

A C1 classification means the building is extremely dangerous, beyond repair, and must be vacated and demolished immediately. The municipal corporation issues an evacuation notice and a demolition order. Residents must relocate, and in Mumbai, MHADA may provide transit accommodation for eligible tenants. The building plot then becomes eligible for redevelopment.

Can a housing society challenge a C1 classification?

Yes. In Maharashtra, a housing society can appoint another registered structural engineer for a second opinion. If the two reports disagree, the matter can be referred to the municipal corporation's technical advisory committee. Legal challenges through the Bombay High Court are also possible, though courts generally defer to engineering assessments.

How often should a structural audit be repeated?

In Maharashtra, buildings over 30 years must be audited every 5 years and buildings between 15-30 years every 10 years. In Gujarat, the frequency varies by building class (every 15 years for Class 1 buildings). For buildings in other states, best practice is to conduct a structural audit every 10 years after the building reaches 20 years of age, or immediately after any earthquake, fire, flood, or significant structural modification.

What is the difference between a structural audit and a seismic evaluation?

A structural audit assesses the overall structural health of a building — concrete strength, reinforcement condition, foundation stability, and compliance with current codes. A seismic evaluation (per IS 15988:2013) specifically assesses whether the building can resist earthquake forces as defined by the current seismic code (IS 1893). A comprehensive structural audit in seismic zones III, IV, and V should include a seismic evaluation component.

Does RERA cover structural defects?

Yes. Under Section 14(3) of RERA 2016, developers are liable for structural defects for 5 years from the date of possession. If a structural defect is found within this period, the developer must rectify it at their own cost within 30 days of receiving notice. If the developer fails to act, the allottee can file a complaint with the state RERA authority for compensation.

Can I conduct a structural audit on my individual flat?

A structural audit covers the entire building, not individual units. The structural system (columns, beams, slabs, foundations) is shared among all residents. A housing society or building owner must commission the audit for the complete structure. However, if you notice cracks, dampness, or other signs of structural distress in your flat, you should report them to the society and request a building-wide structural audit.

What qualifications should a structural auditor have?

In Mumbai, the engineer must be registered on BMC's panel (B.E. Civil + 10 years experience). In other cities, look for: B.E./B.Tech in Civil Engineering, minimum 5-10 years of experience in structural design and assessment, membership of the Institution of Engineers (India) or IAStructE accreditation, and registration with the local municipal corporation where such registration exists.

How long does a structural audit take?

For a typical 5-floor residential building: visual inspection takes 1-2 days, NDT testing takes 2-3 days, laboratory testing (if cores are extracted) takes 7-10 days, structural analysis and report preparation takes 5-7 days. Total timeline: approximately 3-4 weeks from site visit to final report submission. Larger or more complex buildings may take 6-8 weeks.